bullet: read the label
flatten: handle top-level non-actions

They may be referenced.
fire: read the label
test: test files individually
test: add a test for resolving files
test: use my fork

The original repo has filenames which can't be handled in CTest nicely
(they contain parentheses).
flatten: default parameter value is '1'

From the reference implementation.
resolve: rename flatten.d to resolve.d
resolve: don't fully resolve action trees

Some actions are recursive and as such cannot be fully resolved.
Instead, have the ORef structure store a pointer to the target item.
runner: ignore top-level non-actions